[英語學(xué)習(xí)]楊陽翻譯

1、.光電技術(shù)學(xué)院畢業(yè)生文獻(xiàn)翻譯光纖通信系統(tǒng)仿真及常用通信接口技術(shù)學(xué)生姓名：楊 陽專 業(yè)：光信息科學(xué)與技術(shù)班 級：光信息2007級1班導(dǎo)師姓名(職稱)：程 科（講師）文獻(xiàn)提交日期：2010年5月22日*;光纖通信系統(tǒng)仿真及常用通信接口技術(shù)摘要本文介紹了光纖通信的發(fā)展方向，闡述了系統(tǒng)仿真的特點(diǎn)及國內(nèi)外的發(fā)展?fàn)顩r，第二部分為現(xiàn)用通信接口中常用接口討論。關(guān)鍵詞： 光纖通信，發(fā)展方向，系統(tǒng)仿真，接口1 概述1.1 光纖通信在“信息高速公路”的概念被提出以后，光纖通信技術(shù)在加大容量和延長通信距離方面取得了突飛猛進(jìn)的發(fā)展。寬帶光纖放大器W-EDFA（Wide band Erbium-Doped Fiber A

2、mplifier）和密集波分復(fù)用是光纖通信技術(shù)發(fā)展最引人矚目的方向。為了降低損耗和色散設(shè)計(jì)了色散位移光纖DSF（Dispersion Shifted Fiber），在1525-1565nm波段內(nèi)，色散降至2-3ps/（nm·km）間；在1540nm色散為零。為減小DWDM系統(tǒng)的四波混頻效應(yīng)，還設(shè)計(jì)了一種新型的非零色散光纖NZDF（Non-Zero Dispersion Fiber）。與此同時(shí)，光電子集成技術(shù)（OEIC）也在飛速發(fā)展，垂直腔面發(fā)射激光器VCSEL（Vertical Ca-vity Surface Emitting Laser）和光電接收機(jī)已經(jīng)實(shí)現(xiàn)了光電子集成。光的時(shí)分多

3、種（OTDM）目前國際上也有單位積極從事研究。光纖常被電話公司用于傳遞電話、互聯(lián)網(wǎng)，或是有線電視的信號，有時(shí)候利用一條光纖就可以同時(shí)傳遞上述的所有信號。與傳統(tǒng)的銅線相比，光纖的信號衰減與遭受干擾的情形都改善很多，特別是長距離以及大量傳輸?shù)氖褂脠龊现?，光纖的優(yōu)勢更為明顯。然而，在城市之間利用光纖的通信基礎(chǔ)建設(shè)通常施工難度以及材料成本難以控制，完工后的系統(tǒng)維運(yùn)復(fù)雜度與成本也居高不下。因此，早期光纖通信系統(tǒng)多半應(yīng)用在長途的通信需求中，這樣才能讓光纖的優(yōu)勢徹底發(fā)揮，并且抑制住不斷增加的成本。從2000年光通信市場崩潰后，光纖通信的成本也不斷下探，目前已經(jīng)和銅纜為骨干的通信系統(tǒng)不相上下。對于光纖通信產(chǎn)業(yè)

4、而言，1990年光放大器正式進(jìn)入商業(yè)市場的應(yīng)用后，很多超長距離的光纖通信才得以真正實(shí)現(xiàn)，例如越洋的海底電纜。到了2002年時(shí)，越洋海底電纜的總長已經(jīng)超過25萬公里，每秒能攜帶的數(shù)據(jù)量超過2.56Tb，而且根據(jù)電信業(yè)者的統(tǒng)計(jì)，這些數(shù)據(jù)從2004年后仍然不斷的大幅成長中。1.2光纖通信的歷史1966年查爾斯·K·Kao和喬治·hockom在位于英國哈洛區(qū)的STC實(shí)驗(yàn)室(STL)提出了光纖，他們表示，在現(xiàn)有玻璃中擁有 1000 dB/km損失 (對比于同軸電纜的5-10 db/km)應(yīng)歸結(jié)于污染物，可能會(huì)被潛在地去除。1970年代康寧公司成功的開發(fā)出高品質(zhì)低衰減的光纖，

5、此時(shí)信號在光纖中傳遞的衰減量第一次低于光纖通信之父高錕所提出的每公里衰減20分貝關(guān)卡，證明了光纖作為通信介質(zhì)的可能性。與此同時(shí)使用砷化鎵作為材料的用于長距離傳送的半導(dǎo)體激光也被發(fā)明出來，并且憑借著體積小的優(yōu)勢而大量運(yùn)用于光纖通信系統(tǒng)中。從1975年開始的一段研究時(shí)期過后，第一個(gè)光纖通信系統(tǒng)誕生了，使用波長800納米并且使用砷化鎵激光作為光源。這個(gè)第一代系統(tǒng)傳輸?shù)乃俾蔬_(dá)到45Mb/s，每10公里需要一個(gè)中繼器增強(qiáng)信號。很快于1977年4月22日，在加利福尼亞的長灘普通電話和電子通過光纖通信以6 Mbit/s傳輸速率送出了第一通現(xiàn)場連接的通話業(yè)務(wù)。第二代的商用光纖通信系統(tǒng)也在1980年代初期就發(fā)展

6、出來，使用波長1300納米的磷砷化鎵銦激光。早期的光纖通信系統(tǒng)雖然受到色散）的問題而影響了信號品質(zhì)，但是1981年單模光纖的發(fā)明克服了這個(gè)問題。到了1987年時(shí)，一個(gè)商用光纖通信系統(tǒng)的傳輸速率已經(jīng)高達(dá)1.7Gb/s，比第一個(gè)光纖通信系統(tǒng)的速率快了將近四十倍之譜。同時(shí)傳輸?shù)墓β逝c信號衰減的問題也有顯著改善，間隔50公里才需要一個(gè)中繼器增強(qiáng)信號。1980年代末，EDFA的誕生，堪稱光通信歷史上的一個(gè)里程碑似的事件，它使光纖通信可直接進(jìn)行光中繼，使長距離高速傳輸成為可能，并促使了DWDM的誕生。第三代的光纖通信系統(tǒng)改用波長1550納米的激光做光源，而且信號的衰減已經(jīng)低至每公里0.2分貝。之前使用磷砷

7、化鎵銦激光的光纖通信系統(tǒng)常常遭遇到脈波延散問題，而科學(xué)家則設(shè)計(jì)出色散遷移光纖來解決這些問題，這種光纖在傳遞1550納米的光波時(shí)，色散幾乎為零，因其可將激光光的光譜限制在單一縱模。這些技術(shù)上的突破使得第三代光纖通信系統(tǒng)的傳輸速率達(dá)到2.5Gb/s，而且中繼器的間隔可達(dá)到100公里遠(yuǎn)。第四代光纖通信系統(tǒng)引進(jìn)了光放大器，進(jìn)一步減少中繼器的需求。另外，波分復(fù)用技術(shù)則大幅增加傳輸速率。這兩項(xiàng)技術(shù)的發(fā)展讓光纖通信系統(tǒng)的容量以每六個(gè)月增加一倍的方式大幅躍進(jìn)，到了2001年時(shí)已經(jīng)到達(dá)10Tb/s的驚人速率，足足是80年代光纖通信系統(tǒng)的200倍之多。近年來，傳輸速率已經(jīng)進(jìn)一步增加到14Tb/s，每隔160公里才

8、需要一個(gè)中繼器。第五代光纖通信系統(tǒng)發(fā)展的重心在于擴(kuò)展波分復(fù)用器的波長操作范圍。傳統(tǒng)的波長范圍，也就是一般俗稱的“C band”約是1530納米至1570納米之間，新一帶的無水光纖低損耗的波段則延伸到1300納米至1650納米間。另外一個(gè)發(fā)展中的技術(shù)是引進(jìn)光孤子的概念，利用光纖的非線性效應(yīng)，讓脈波能夠抵抗色散而維持原本的波形。1990年至2000年間，光纖通信產(chǎn)業(yè)受到互聯(lián)網(wǎng)泡沫的影響而大幅成長。此外一些新興的網(wǎng)絡(luò)應(yīng)用，如隨選視頻使得互聯(lián)網(wǎng)帶寬的成長甚至超過摩爾定律所預(yù)期集成電路芯片中晶體管增加的速率。而自互聯(lián)網(wǎng)泡沫破滅至2006年為止，光纖通信產(chǎn)業(yè)通過企業(yè)整并壯大規(guī)模，以及委外生產(chǎn)的方式降低成本

9、來延續(xù)生命。現(xiàn)在的發(fā)展前沿就是全光網(wǎng)絡(luò)了，使光通信完全的代替電信號通訊系統(tǒng)，當(dāng)然，這還有很長的路要走。1.3 系統(tǒng)的仿真 系統(tǒng)仿真是近二十年發(fā)展起來的一門新興技術(shù)科學(xué)。所謂計(jì)算機(jī)仿真就是在計(jì)算機(jī)上利用模型對實(shí)際系統(tǒng)進(jìn)行實(shí)驗(yàn)研究的過程。利用計(jì)算機(jī)仿真可以多次重復(fù)模擬客觀世界的同一現(xiàn)象，從而得以找出其內(nèi)在規(guī)律。尤其對含有隨機(jī)變量和隨機(jī)過程，難以建立數(shù)學(xué)模型的客觀事物的研究，計(jì)算機(jī)仿真方法具有突出的優(yōu)點(diǎn)，已成為分析、研究和設(shè)計(jì)各種系統(tǒng)的重要手段。把計(jì)算機(jī)仿真技術(shù)應(yīng)用到通信領(lǐng)域就是其中的一項(xiàng)重要分支。隨著通信技術(shù)的發(fā)展，通信網(wǎng)絡(luò)的數(shù)量和復(fù)雜度的迅速增長，在通信系統(tǒng)設(shè)計(jì)中運(yùn)用計(jì)算機(jī)仿真技術(shù)已成為新系統(tǒng)設(shè)

10、計(jì)時(shí)縮短設(shè)計(jì)周期、提高設(shè)計(jì)可靠性和已有系統(tǒng)性能改進(jìn)的不可缺少的工具。2 光纖通信系統(tǒng)的仿真 光纖通信技術(shù)是一門多學(xué)科專業(yè)交叉滲透的綜合技術(shù)。它涉及到通信基礎(chǔ)理論（如數(shù)字通信技術(shù)），微波技術(shù)（如光纖信道的電磁場分析）以及電路設(shè)計(jì)與微電子技術(shù)（如ASIC專用集成電路）等。因此，無論是系統(tǒng)的規(guī)劃與設(shè)計(jì)，還是新型傳輸系統(tǒng)與體制的探索與研究，都要遇到冗長繁雜的計(jì)算。此外，為了驗(yàn)證其性能是否合科要求，還需反復(fù)進(jìn)行實(shí)驗(yàn)研究與測試。如果每次都直接用真實(shí)系統(tǒng)進(jìn)行實(shí)驗(yàn)，不僅耗資昂貴，費(fèi)工費(fèi)時(shí)，有時(shí)甚至難于找到問題癥結(jié)所在，因此，解決上述問題的有效方法是采用計(jì)算機(jī)仿真技術(shù)，即通過建立器件部件乃至系統(tǒng)的模型，并用模型

11、在計(jì)算機(jī)上做實(shí)驗(yàn)，利用計(jì)算機(jī)的高速運(yùn)算處理能力，完成對光纖通信設(shè)備與系統(tǒng)的分析、設(shè)計(jì)以及性能優(yōu)化與評估測試。2.1 光纖通信系統(tǒng)仿真軟件的現(xiàn)狀 仿真分為電路仿真和系統(tǒng)級仿真。電路級仿真就是由電阻、電容、電感等組成等效的電路模型來模擬器件的外特性。系統(tǒng)級仿真是肜傳輸函數(shù)或數(shù)字公式來模擬器件的外特性的模擬。國外已有一些光纖通信系統(tǒng)仿真軟件，用于電路分析時(shí)，其側(cè)重點(diǎn)不同，例如Boss是一種界面友好的光鏈路仿真軟件，它包括光纖器件模型，但只適用于單一波長系統(tǒng)。SCOPE（Super Co-mpact Optoelectronic Simulation）是一種把系統(tǒng)的光電器件和光器件用兩端口網(wǎng)絡(luò)模型來模

12、擬的非線性微波仿真軟件，其主要用途是對在微波頻率的IM/DD光通信系統(tǒng)進(jìn)行仿真。DEX SOLUS（Simulation of Light Using Spice）是基于Spice電路仿真軟件的專用于光通信領(lǐng)域的信號分析軟件，它采用等效電路模型來模擬光電器件，這些模型的光功率在仿真中用電壓來表征。還有其它電路級的仿真軟件如iSMILE和MISIM等。IBM的OLAP（Optical Link Analysis Program）是一個(gè)把SYSTID和低級的光器件仿真軟件綜合起來應(yīng)用的軟件。還有一些新的仿真軟件如iFROST（illinois FibeR-optic and Optoelectro

13、nic Systems Toolkit）等，用戶可調(diào)用其他仿真軟件來提供混合級的仿真環(huán)境。3 常用通信接口技術(shù)的探討3.1與串并行轉(zhuǎn)換器相連的光電器件在高速光纖通信系統(tǒng)中，傳輸?shù)臄?shù)據(jù)流需要進(jìn)行格式轉(zhuǎn)換，即在光纖傳輸時(shí)的串行格式及在電子處理時(shí)的并行格式之間轉(zhuǎn)換。串行器-解串器(一般被稱作串并行轉(zhuǎn)換器)就是用來實(shí)現(xiàn)這種轉(zhuǎn)換的。串并行轉(zhuǎn)換器與光電傳感器間的接口通常為高速串行數(shù)據(jù)流，利用一種編碼方案實(shí)現(xiàn)不同信令，這樣可從數(shù)據(jù)恢復(fù)嵌入時(shí)鐘。根據(jù)所支持的通信標(biāo)準(zhǔn)，該串行流可在1.25Gb/s(千兆以太網(wǎng))、2.488Gb/s(OC-48/STM-16)、9.953Gb/s(OC-192/STM-64)或1

14、0.3Gb/s(10千兆以太網(wǎng))條件下傳輸。3.2串并行轉(zhuǎn)換器至成幀器接口在Sonet/SDH的世界中，光纖中的數(shù)據(jù)傳輸往往采用幀的形式。每幀包括附加信息(用于同步、誤差監(jiān)視、保護(hù)切換等)和有效載荷數(shù)據(jù)。傳輸設(shè)備必須在輸出數(shù)據(jù)中加入幀的附加信息，接收設(shè)備則必須從幀中提取有效載荷數(shù)據(jù)，并用幀的附加信息進(jìn)行系統(tǒng)管理。這些操作都會(huì)在成幀器中完成。由于成幀器需要實(shí)現(xiàn)某些復(fù)雜的數(shù)字邏輯，因而決定了串并行轉(zhuǎn)換器與成幀器間所用的接口技術(shù)，采用標(biāo)準(zhǔn)CMOS工藝制造的高集成度IC。目前的CMOS工藝不能支持10Gb/s串行數(shù)據(jù)流，因此串并行轉(zhuǎn)換器與成幀器間需要并行接口。目前最流行的選擇是由光網(wǎng)絡(luò)互聯(lián)論壇(Opt

15、ical Internetworking Forum)開發(fā)的SFI-4，該接口使用兩個(gè)速度達(dá)622Mb/s的16位并行數(shù)據(jù)流(每個(gè)方向一個(gè))。SFI-4與目前很多新型接口一樣，使用源同步時(shí)鐘，即時(shí)鐘信號與數(shù)據(jù)信號共同由傳輸器件傳輸。源同步時(shí)鐘可顯著降低時(shí)鐘信號與數(shù)據(jù)信號間的偏移，但它不能完全消除不匹配PCB線路長度引起的偏移效應(yīng)。16個(gè)數(shù)據(jù)信號和時(shí)鐘信號均使用IEEE-1593.6標(biāo)準(zhǔn)LVDS信令。該接口僅需在串并行轉(zhuǎn)換器與成幀器間來回傳輸數(shù)據(jù)，距離較短，因此無須具備復(fù)雜的流控制或誤差檢測功能。力及對操作系統(tǒng)中電路板的可能損害。其二，在信號中嵌入時(shí)鐘和數(shù)據(jù)的串行接口可完全避免時(shí)鐘偏移問題。時(shí)鐘

16、偏移是PCB中數(shù)英寸長的并口所面臨的主要問題。其三，串行信號的背板設(shè)計(jì)者還可提高傳輸速率，因?yàn)椴淮嬖跁r(shí)鐘偏移，也就沒有對未來性能的限制。被成功用作串行背板標(biāo)準(zhǔn)的接口是XAUI，它是為10千兆以太網(wǎng)開發(fā)的。該規(guī)范適用于通道排列電路，無論四通道軌線長度是否匹配，符合XAUI的器件均能接收無誤差數(shù)據(jù)。該接口使用差分電流模式邏輯信令，它還采用交流耦合模式，允許電路板間的參考電壓不同。3.3 控制板接口已獲得Motorola及Rapid IO貿(mào)易聯(lián)合會(huì)支持的Rapid IO是使用交換架構(gòu)實(shí)現(xiàn)點(diǎn)至點(diǎn)鏈接的接口。該接口的傳輸層規(guī)定數(shù)據(jù)如何封裝在包中，每個(gè)包都具有數(shù)據(jù)源和目標(biāo)信息，交換架構(gòu)將數(shù)據(jù)包送往合適的目

17、的地。Rapid IO在每個(gè)方向上提供8個(gè)或16個(gè)位，采用250MHz1.0GHz雙數(shù)據(jù)速率。此外，串行Rapid IO可使用具有8b/10b編碼的1通道或4通道數(shù)據(jù)，嵌入時(shí)鐘達(dá)3.125Gb/s，它還具有CML差分信令。AMD及Hyper Transport聯(lián)盟開發(fā)的Hyper Transport使用通道器件實(shí)現(xiàn)點(diǎn)至點(diǎn)鏈接。數(shù)據(jù)以包的形式傳輸，每個(gè)包均包括數(shù)據(jù)源和目標(biāo)信息。接收數(shù)據(jù)的通道器件按照數(shù)據(jù)包報(bào)頭確定是將數(shù)據(jù)傳至鏈中的下一個(gè)器件，還是直接處理數(shù)據(jù)。目前的Hyper Transport規(guī)范需要寬度為216位的并行數(shù)據(jù)。未來規(guī)范可支持更高速率。PMC-Sierra和Bro AD Com已

18、經(jīng)為Hyper Transport通信產(chǎn)品推出基于MIPS的處理器。PCI-SIG已經(jīng)推出高速率PCI-X。它們使用與最初PCI-X相同的64位總線帶寬，可支持雙數(shù)據(jù)速率和四倍數(shù)據(jù)速率。PCI-X 533是速率最快的版本，最大總計(jì)帶寬達(dá)34.1Gb/s。PCIX的傳輸通訊協(xié)議、訊號和標(biāo)準(zhǔn)的接頭格式都與PCI一并兼容，可以使3.3V的32位PCI適配卡可以用在PCI-X擴(kuò)充槽上。當(dāng)然如果你愿意，也可以將64位PCI-X適配卡接在32位PCI擴(kuò)充槽上，不過，頻寬速度將會(huì)大減。4 結(jié)束語目前，我國在光纖通信系統(tǒng)仿真研究方面已經(jīng)起步，如清華大學(xué)、天津大學(xué)等均取得一些成績，設(shè)計(jì)一個(gè)功能較強(qiáng)，性能可靠的光

19、纖通信系統(tǒng)的仿真軟件包，對適應(yīng)光纖通信的飛速發(fā)展有著重要的理論意義和現(xiàn)實(shí)意義，具有較高的性價(jià)比和廣泛的應(yīng)用前景。Optical Fiber Communication System Simulation and Common Communication Interface TechnologyAbstractThis paper describes the development direction of optical fiber communications, described the characteristics of system simulation and developmen

20、t at home and abroad. The second part is commonly used by communication interface interface discussion.Keywords Opticalfibercommunications ,development, SystemSimulation , Interface1 Outline1.1 Optical Fiber CommunicationIn the "information superhighway" concept was put forward after the o

21、ptical fiber communication technology in increasing the capacity and extend the communication distance has made rapid development. Broadband fiber amplifier W-EDFA (Wide band Erbium-Doped Fiber Amplifier) and dense wavelength division multiplexing optical fiber communication technology development i

22、s the most eye-catching direction. Loss and dispersion in order to reduce the design of the dispersion shifted fiber DSF (Dispersion Shifted Fiber), in the 1525-1565nm band, the dispersion fell to -2 - +3 ps / (nm km) between; zero dispersion at 1540nm. DWDM systems to reduce four-wave mixing effect

23、, but also designed a new type of non-zero dispersion fiber NZDF (Non-Zero Dispersion Fiber). At the same time, integrated opto-electronics technologies (OEIC) is the rapid development of vertical-cavity surface-emitting laser VCSEL (Vertical Ca-vity Surface Emitting Laser) and electro-optical recei

24、ver optoelectronic integration has been achieved. Around a variety of light (OTDM) At present, there are active in research units.Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. Due to much lower attenuat

25、ion and interference, optical fiber has large advantages over existing copper wire in long-distance and high-demand applications. However, infrastructure development within cities was relatively difficult and time-consuming, and fiber-optic systems were complex and expensive to install and operate.

26、Due to these difficulties, fiber-optic communication systems have primarily been installed in long-distance applications, where they can be used to their full transmission capacity, offsetting the increased cost. Since 2000, the prices for fiber-optic communications have dropped considerably. The pr

27、ice for rolling out fiber to the home has currently become more cost-effective than that of rolling out a copper based network. Prices have dropped to $850 per subscriber in the US and lower in countries like The Netherlands, where digging costs are low.Since 1990, when optical-amplification systems

28、 became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines. By 2002, an intercontinental network of 250,000 km of submarine communications cablewith a capacity of 2.56 Tb/s was completed, and although specific netwo

29、rk capacities are privileged information, telecommunications investment reports indicate that network capacity has increased dramatically since 2004.1.2 The history of fiber-optic communications In 1966 Charles K. Kao and George hockom proposed optical fibers at STC Laboratories (STL) at Harlow, Eng

30、land, when they showed that the losses of 1000 dB/km in existing glass (compared to 5-10 db/km in coaxial cable) was due to contaminants, which could potentially be removed.Optical fiber was successfully developed in 1970 by Corning Glass Works, with attenuation low enough for communication purposes

31、 (about 20dB/km), and at the same time GaAs semiconductor lasers were developed that were compact and therefore suitable for transmitting light through fiber optic cables for long distances.After a period of research starting from 1975, the first commercial fiber-optic communications system was deve

32、loped, which operated at a wavelength around 0.8 µm and used GaAs semiconductor lasers. This first-generation system operated at a bit rate of 45 Mbps with repeater spacing of up to 10 km. Soon on 22 April, 1977, General Telephone and Electronics sent the first live telephone traffic

33、through fiber optics at a 6 Mbit/s throughput in Long Beach, California.The second generation of fiber-optic communication was developed for commercial use in the early 1980s, operated at 1.3 µm, and used InGaAsP semiconductor lasers. Although these systems were initially limited by dispersion,

34、 in 1981 the single-mode fiber was revealed to greatly improve system performance. By 1987, these systems were operating at bit rates of up to 1.7 Gb/s with repeater spacing up to 50 km.The first transatlantic telephone cable to use optical fiber was TAT-8, based on Desurvire optimized laser am

35、plification technology. It went into operation in 1988.Third-generation fiber-optic systems operated at 1.55 µm and had losses of about 0.2 dB/km. They achieved this despite earlier difficulties with pulse-spreading at that wavelength using conventional InGaAsP semiconductor lasers. Scient

36、ists overcame this difficulty by using dispersion-shifted fibers designed to have minimal dispersion at 1.55 µm or by limiting the laser spectrum to a single longitudinal mode. These developments eventually allowed third-generation systems to operate commercially at 2.5 Gbit/s with repeater spa

37、cing in excess of 100 km.The fourth generation of fiber-optic communication systems used optical amplification to reduce the need for repeaters and wavelength-division multiplexing to increase data capacity. These two improvements caused a revolution that resulted in the doubling of system capa

38、city every 6 months starting in 1992 until a bit rate of 10 Tb/s was reached by 2001. Recently, bit-rates of up to 14 Tbit/s have been reached over a single 160 km line using optical amplifiers.The focus of development for the fifth generation of fiber-optic communications is on extending the w

39、avelength range over which a WDM system can operate. The conventional wavelength window, known as the C band, covers the wavelength range 1.53-1.57 µm, and the new dry fiber has a low-loss window promising an extension of that range to 1.30-1.65 µm. Other developments include the concept o

40、f “optical solitons, “ pulses that preserve their shape by counteracting the effects of dispersion with the nonlinear effectsof the fiber by using pulses of a specific shape.In the late 1990s through 2000, industry promoters, and research companies such as KMI and RHK predicted vast increases in dem

41、and for communications bandwidth due to increased use of the Internet, and commercialization of various bandwidth-intensive consumer services, such as video on demand .Internet protocoldata traffic was increasing exponentially, at a faster rate than integrated circuit complexity had increased under

42、Moores Law. From the bust of the dot-com bubble through 2006, however, the main trend in the industry has been consolidation of firms and offshoring of manufacturing to reduce costs. Recently, companies such as Verizon and AT&T have taken advantage of fiber-optic communications to deliver a vari

43、ety of high-throughput data and broadband services to consumers homes.1.3 System SimulationSystem simulation is developed in the last two decades a science and emerging technologies. Is the so-called computer simulation model on the computer system for experimental study of the actual process. The u

44、se of computer simulation can be repeated simulation of the same phenomenon of the objective world and thus to find out the inherent laws. In particular, contain random variables and random process, it is difficult to establish a mathematical model of an objective study of things, the computer simul

45、ation method has obvious advantages, has become the analysis, research and design of an important means of various systems. The application of computer simulation technology to the field of communications is one of an important branch. With the development of communication technologies, communicatio

46、ns networks, the number and complexity of the rapid growth of the design of communication systems in use of computer simulation technology has become a new system designed to shorten the design cycle and improve design reliability and improved system performance has been an indispensable tool.2 Opti

47、cal fiber communication system simulationOptical fiber communication technology is more than one cross-discipline integrated technology penetration. It involves the basic theory of communication (such as digital communication technology), and microwave technologies (such as fiber channel analysis of

48、 electromagnetic fields), as well as circuit design and microelectronic technology (such as application specific integrated circuit ASIC) and so on. Therefore, whether it is systematic planning and design, or a new type of transmission system and the system of exploration and research, have experien

49、ced lengthy complicated calculations. In addition, in order to verify whether the performance requirements of Section need to research and experiment repeated testing. If every time the direct use of the real system experiments, not only the cost of expensive, labor-and time-consuming and sometimes

50、difficult to find the crux of the problem, therefore, address these problems is an effective means of computer simulation techniques, namely through the establishment of device components and the system model , and model experiments on the computer, using high-speed computer processing capacity, com

51、pletion of the fiber-optic communications equipment and systems analysis, design optimization and performance testing and evaluation.2.1 Optical fiber communication system simulation software, the status quoThe simulation is divided into circuit simulation and system-level simulation. Circuit-level

52、simulation by resistors, capacitors, inductors and other components of the circuit model equivalent to the outer characteristics of Analog Devices. System-level simulation is Rong transfer function or the number of formula characteristics of analog simulation. Abroad, some optical fiber communicatio

53、n system simulation software for circuit analysis, focusing on different, such as the Boss is a user-friendly optical link simulation software, which includes fiber-optic device model, but only in a single wavelength system. SCOPE (Super Co-mpact Optoelectronic Simulation) is a kind of the photovolt

54、aic devices and optical devices using the two-port network model to simulate the nonlinear microwave simulation software, its main use is in the microwave frequency of IM / DD Optical Communication Systems simulation. DEX SOLUS (Simulation of Light Using Spice) is based on the Spice circuit simulati

55、on software dedicated to the field of optical communication signal analysis software, it uses the equivalent circuit model to simulate optoelectronic devices, optical power of the models used in the simulation of voltage to represent . There are other circuit-level simulation software such as iSMILE

56、 and MISIM. IBM's OLAP (Optical Link Analysis Program) is a low-level to SYSTID and simulation software of optical devices integrated with software applications. There is a number of new simulation software, such as iFROST (Illinois FibeR-optic and Optoelectronic Systems Toolkit), etc., the user

57、 can call other simulation software to provide a mixed-level simulation environment.3 Common Communication Interface Technology3.1 Converters in parallel with the string attached to optoelectronic devices In high-speed optical fiber communication systems, transmission of data stream format conversio

58、n is required, that is, at the time of optical transmission in serial form and in electronic format when the parallel between the conversion. Serializer - deserializer (generally known as the Serial and Parallel converter) is used to achieve this conversion. Serial and Parallel converter and the int

59、erface between the photoelectric sensor is usually high-speed serial data stream, using a different coding schemes signaling, this can be embedded clock data recovery. According to the communication standards supported by the serial stream can be 1.25Gb / s (Gigabit Ethernet), 2.488Gb / s (OC-48/STM-16), 9.953Gb / s (OC-192/STM- 64) or 10.3Gb / s (10 Gigabit Ethernet) transmission conditions.3.2 Serial and Parallel interface converter to the framers In the Sonet